An Oregon lawmaker is looking to restrict household use of four common pesticides that pose risks to bees.

Rep. Jeff Reardon, D-Portland, says given the toxicity of certain pesticides and their track record for killing bees, untrained home gardeners shouldn't be allowed to use them.

Reardon is planning to introduce a bill that would require a license and training to apply the pesticides clothianidin, dinotefuran, imidacloprid and thiamethoxam. All four belong to a family of chemicals known as neonicotinoids, and studies have shown they can be toxic to bees.

Last summer, an estimated 50,000 bumblebees near a Wilsonville Target store were killed by an ill-timed application of the pesticide Safari, which contains the neonicotinoid dinotefuran. The company that applied the pesticide, Collier Arbor Care, was fined $2,800 for spraying the chemical on blooming linden trees in violation of instructions on the label.

Neonicotinoids are also found in household products such as Bayer and Ortho insecticides, and they're commonly sold at garden stores. Reardon says the fact that a professional pesticide applicator could accidentally kill so many bees has him worried about household use of such chemicals.

"What concerns me is that home gardeners really don’t have that degree of training," Reardon says. "They aren’t tested. We rely on them reading and following the directions on the label. People who have passed the test can make mistakes that kill tens of thousands of bees, I question how reasonable it is to assume home gardeners are going to have better results."

Following the bee die-off in Wilsonville, U.S. Rep. Earl Blumenauer, D-OR, introduced a bill that would ban the use of neonicotinoid pesticides nationwide until the Environmental Protection Agency completes a review of their impacts. However, the bill hasn't moved since he introduced it.

The Oregon Department of Agriculture responded to the incident by adding its own restrictions to the use of two neonicotinoid pesticides. The state now prohibits the application of dinotefuran and imidicloprid on basswood and linden trees because those trees have a natural toxicity that increases the risk of pesticides killing pollinators.

Reardon's bill would take the state restrictions a significant step further by preventing unlicensed home gardeners from using four neonicotinoid pesticides at all. It also requires the state to implement special training and testing to ensure licensed pesticide applicators know how to minimize risk to pollinators.

Environmental groups including the Oregon League of Conservation Voters and the Xerces Society, an insect conservation group, helped draft the bill.

Scott Hoffman Black, executive director of the Xerces Society, says the four pesticides the bill restricts are the most toxic of all neonicotinoids and the most long-lived in plants and soil.

"We really believe that because these four specific chemicals are so toxic and so long-lived in the environment that the EPA should really pull them until we understand the real impacts — not just on bees but on insects that salmon feed on," Black says. "We believe these are having wide-range impacts."

The industry group Oregonians for Food and Shelter, which represents companies that make pesticides as well as people and industries that use them, is opposing the bill.

Scott Dahlman, the group's executive director, says the products Reardon is looking to restrict are also the most commonly used household pesticides. And, he says, there’s no evidence that household pesticide use is causing mass bee die-offs like the one in Wilsonville.

"We feel like they’re putting the cart before the horse here," Dahlman says. "It seems like there’s an attempt to restrict the use of these products when we’re not seeing a link between their general use and the deaths of bees. We all agree if these products are used improperly they could pose a risk."

Others are also skeptical that restricting household use of neonicotinoids is the right idea.

Paul Jepson is the director of Oregon State University’s Integrated Plant Protection Center. Part of his job is looking for pesticide alternatives and studying their effectiveness. He's been asked to study alternatives to the neonicotinoids that would be restricted in Reardon's bill.

Jepson says he suspects the use of neonicotinoid pesticides is widespread among home gardeners based on their prevalence at garden stores. There are less toxic alternatives to neonicotinoids, he says, but they can be more expensive or more labor intensive. There are also more toxic alternatives.

He says there is a risk that gardeners will switch to other harmful chemicals if they can’t use neonicotinoids.

“I look at some of the other compounds out there, and some of them pose even higher risks,” Jepson says.

The best solution, he suggests, is for gardeners to manage their plants in a way that makes them less vulnerable to unwanted insects.

“Don't rely just on things that are in bottles,” he says. “We're just somewhat dismayed that you often ask why a person is using a chemical and it turns out they're actually gardening in a way that makes their plants more susceptible to pests.”